Jamb Chemistry 1985 Past Questions and Answers

Question 21:

• JAMB 1985

Which of the following compounds is NOT the correct product formed when the parent metals is heated in air?

A. Calcium oxide (CaO)
B. Sodium oxide (Na₂O)
C. Copper (ll) oxide (CuO)
D. Tri-iron tetroxide (Fe₃O₄)
E. Aluminium oxide (Al₂O₃)

Question 22:

• JAMB 1985

The atomic number of an element whose cation, X²⁺, has the ground state electronic configuration 1s²2s²2p⁶3s²2p⁶ is?

A. 16
B. 18
C. 20
D. 22
E. 24

Question 23:

• JAMB 1985

When marble is heated to about 1473 K, another white solid is obtained which reacts vigorously with water to give an alkaline solution. The solution contains?

A. NaOH
B. KOH
C. Mg(OH)₂
D. Zn(OH)₂
E. Ca(OH)₂

Question 24:

• JAMB 1985

Addition of dilute hydrochloride acid to an aqueous solution of a crystalline salt yield a yellow precipitate and a gas which turned dichromate paper green. The crystalline salt was probably?

A. Na₂SO₄
B. Na₂S
C. Na₂S₂O₃.5H₂O
D. Na₂CO₃
E. NaHCO₃

Question 25:

• JAMB 1985

The process involved in the conversion of an oil into margarine is known as?

A. Hydrogenation
B. Condensation
C. Pyrolysis
D. Dehydration
E. Cracking